The tasks of a network are divided into several entities, called layers, that handle specified tasks. For example, it is possible to separate four distinct layers in IP networks: the Link, Network, Transport and Application layer (FIG. 1). In known IP networks signaling handles mainly channel related matters, such as connection set up and connection break off, while management handles element configuration, monitoring, and error messages, for example.
The Network layer is the heart of the IP network. It specifies the format of the Internet packets, called datagrams. Datagrams contain specified fields, such as the destination and the source of the datagram packet. Information is sent by packets which contain the information for routing the packet to the right destination element. The routers in the network must know how to route the packets to the right receiver, so the IP layer also includes a set of rules defining how the packets should be processed.
The Transport layer specifies means for identifying the ultimate destination, i.e. the application in the receiving network element. The two most common ways to handle the transport of a packet are UDP (User Datagram Protocol) and TCP (Transmission Control Protocol). UDP is an unreliable connectionless delivery system, while TCP provides reliable delivery. That means that the TCP sender and receiver must agree that a connection is desired. TCP requires an acknowledgment message from the receiver before the sender is allowed to send more packets. TCP uses a sliding window technique to send acknowledgments. The sliding window indicates the number of packets that a sender can send without receiving an acknowledgment. When the sender gets the acknowledgment concerning the first packet sent, the window slides, making it possible to send a new packet. The receiver can advise the sender what the preferable size for the sliding window is (specifying the receiver's current buffer size). In other words, the sliding window technique can be used for flow control.
The Application layer handles a variety of tasks, such as e-mail and file transport. This layer also contains SNMP (Simple Network Management Protocol) that handles matters such as configuration of network elements and monitoring.
The Link layer consists of a physical network, such as Ethernet and ATM. In ATM networks, for example, it is possible to group several virtual channels together into a virtual path, that is an individual manageable object.
The disadvantage of the known solutions is that there is no common way to handle the allocation of network resources in a packet network, such as an IP network. Known resource allocations are dependent on network characteristics, and thus run on the Link layer. In other words, resource allocation is possible only in the same physical network, such as ATM, but it is impossible to negotiate resource allocation between two network elements in different networks using one common environment. Due to the lack of a common resource allocation method, it is complicated to agree on traffic allocation, for example between operators. Dynamic allocation can also be tedious. The objective of the invention is to eliminate these disadvantages. This is achieved in a way described in the claims.